The Morphological Quality index (MQI) for stream evaluation and hydromorphological classification

Abstract

The general structure of a new methodology, named IDRAIM (sistema IDRomorfologico di valutazione, AnalisI e Monitoraggio dei corsi d’acqua), aimed at a hydromorphological assessment and analysis of streams is presented. In particular, a stream Morphological Quality Index (MQI) developed for the hydromorphological classi cation required by the European Water Framework Directive 2000/60/EC (WFD) is illustrated. The methodological approach is based on integration of eld surveys with remote sensing and GIS analyses. The complete procedure is composed by three parts: initial setting and classi cation; evaluation of the present morphological state and monitoring. The initial classi cation is mainly based on catchment physiographic conditions, channel con nement and morphology. The evaluation of present morphological conditions is carried out by using a series of forms allowing a guided analysis of the following aspects: (a) longitudinal and lateral continuity; (b) channel pattern; (c) crosssectional con guration; (d) bed structure and substrate; and (e) vegetation in the riparian corridor. The analysis is carried out with reference to the foregoing ve aspects by three components: (1) geomorphic functionality; (2) artificiality; (3) channel changes. A scoring system is used to obtain a Morphological Alteration Index (MAI) and a Morphological Quality Index (MQI). It is proposed that the two indices will allow to classify the morphological conditions of a stream. The monitoring phase should then allow for a future assessment of possible variations of the present morphological conditions.